Generation of energy from natural sources, such as sun and wind, has been an important objective in this country over the last several decades. Attempts to reduce reliance on oil, such as from foreign sources, have become an important national issue. Energy experts fear that some of these resources, including oil, gas and coal, may someday run out. Because of these concerns, many projects have been initiated in an attempt to harness energy derived from what are called natural “alternative” sources.
While solar power may be the most widely known alternative source, there is also the potential for harnessing tremendous energy from the wind. Wind farms, for example, have been built in many areas of the country where the wind naturally blows. In many of these applications, a large number of windmills are built and “aimed” toward the wind. As the wind blows against the windmills, rotational power is created and then used to drive generators, which in turn, can generate electricity. This energy is often used to supplement energy produced by utility power plants and distributed by electrical power grids.
Wind farms are best operated when wind conditions are relatively constant and predictable. Such conditions enable a consistent and predictable amount of energy to be generated and supplied, thereby avoiding surges and swings that could adversely affect the system. The difficulty, however, is that wind by its very nature is unpredictable and uncertain. In most cases, wind speeds, frequencies and durations vary considerably, i.e., the wind never blows at the same speed over an extended period of time, and wind speeds themselves can vary significantly from one moment to another. And, because the amount of power generated by wind is mathematically a function of the cube of the wind speed, even the slightest fluctuation or oscillation in wind speed can result in a disproportionate change in wind-generated power. For example, a three-fold change in wind speed (increase or decrease) can result in a twenty-seven-fold change in wind-generated power, i.e., 3 cubed equals 27.
This is particularly significant in the context of a wind farm delivering energy to an electrical power grid, which is a giant network composed of a multitude of smaller networks. These sudden surges in one area can upset other areas and can even bring down the entire system in some cases. Because of these problems, in current systems, wind farm power outputs are often difficult to deal with and can cause problems for the entire system.
Another problem associated with wind fluctuations and oscillations relates to the peak power sensitivity of the transmission lines in the grid. When wind speed fluctuations are significant, and substantial wind power output fluctuations occur, the system must be designed to account for these variances, so that the system will have enough power line capacity to withstand the power fluctuations and oscillations. At the same time, if too much consideration is given to these peak power outputs, the system may end up being over-designed, i.e., if the system is designed to withstand surges during a small percentage of the time, the power grid capacity during the greater percentage of the time may not be used efficiently and effectively.
Another related problem is the temporary loss of wind power associated with an absence of wind or very low wind speed in some circumstances. When this occurs, there may be a gap in wind power supply, which can be detrimental to the overall grid power output. This is especially important when large wind farms are used, wherein greater reliance on wind-generated power, to offset peak demand periods, exists.
Because of these problems, attempts have been made in the past to store energy produced by wind so that wind generated energy can be used during peak demand periods, and/or periods when little or no wind is available, i.e., time-shifting the energy from when it is most available to when it is most needed. Nevertheless, these past systems have failed to be implemented in a reliable and consistent manner. Past attempts have not been able to reduce the inefficiencies and difficulties, as well as the fluctuation and oscillation problems discussed above, inherent in using wind as an energy source for an extended period of time.
Notwithstanding these problems, because wind is a significant natural resource that will never run out, and is often in abundance in many locations throughout the world, there is a desire to develop a method of harnessing power generated by wind, to provide electrical power in a manner that allows not only energy to be stored, but enables the delivery of the energy to the power grid to be coordinated, managed and stabilized, to smooth wind power fluctuations and oscillations, while at the same time, filling in wind energy gaps prior to delivery, such that energy swings and surges that can adversely affect the power grid can be eliminated.